Question

Write a for statement to add all the multiples of 3 between 1 and 100 .

Short answer

Set up a loop from 1 to 100, check if each is a multiple of 3, and sum them.

Step-by-step solution

Initialize the Sum

Begin by initializing a variable to store the sum of the multiples of 3. Set the variable to 0. This will be used to accumulate the total sum as we iterate through the numbers. ```python sum_of_multiples = 0 ```

Set Up the For Loop

Use a for loop to iterate over each number from 1 to 100. We will check each number to see if it is a multiple of 3. ```python for number in range(1, 101): ```

Check for Multiples of 3

Inside the loop, use an if statement to determine if the current number is a multiple of 3. This can be done using the modulo operator, which finds the remainder of division. If the remainder when dividing by 3 is 0, the number is a multiple of 3. ```python if number % 3 == 0: ```

Add the Multiple to the Sum

If the current number is a multiple of 3, add it to the sum variable. This will continue for each multiple found. ```python sum_of_multiples += number ```

Print the Result

Once the loop completes, print out the sum of all multiples of 3 between 1 and 100. ```python print(sum_of_multiples) ```

Key concepts

For Loop

In Python programming, a "for loop" is an essential control structure used to perform repetitive tasks efficiently. It iterates over a sequence (like a list, tuple, or range) and executes a block of code for each element in that sequence.
When using the range function, a "for loop" can quickly iterate through a series of numbers. For instance:

• range(1, 101) generates numbers from 1 to 100.
• Each iteration allows for operations or checks on individual numbers, one by one.

Adding to this, a for loop creates a cleaner and more readable code structure when executing tasks that need to be repeated a specific number of times. This is particularly useful when processing data or automating repetitive tasks, as it reduces manual effort.

Conditional Statements

In computing, conditional statements are used to perform different actions depending on whether a condition evaluates to True or False.
An "if statement" is the most common conditional statement, and it guides decision-making processes in Python.

• It evaluates a condition in parentheses.
• If the condition is True, the code block under the "if statement" is executed.
• If not, the program skips the block.

They are versatile; you can create more advanced decision-making paths, using "elif" and "else" statements. In the context of this exercise, the if statement checks which numbers are multiples of 3, allowing only those to add to the sum.

Modulo Operator

The "modulo operator" (%) plays a critical role in many programming scenarios, especially when dealing with loops and conditional checks. This operator helps in finding the remainder after division between two numbers.
When you see number % 3 == 0, it evaluates if the number is perfectly divisible by 3 or not.

• If a number is perfectly divisible by another, the remainder is 0.
• Thus, this operator can efficiently determine factors or certain properties of numbers, like checking even or odd status.

In the solved example, the modulo operator identifies multiples of 3 by checking when the remainder is 0, thus indicating that they should be added to the sum.

Loops and Iteration

In programming, "loops" are instrumental for automating repetitive tasks, and iteration empowers loops to traverse stores of data, like lists or number ranges.
"Iteration" refers to repeating a block of code for each element in a sequence until every element has been processed.

• A loop typically has a start point and an endpoint (specified in the range function).
• Each cycle through the loop represents one iteration.

Understanding iteration and loops is crucial for writing efficient programs. In particular, they help streamline tasks that involve repeating similar logic. In this exercise, every iteration of the for loop from 1 through 100 manages checking and summing, significantly reducing the manual coding effort to achieve the same results. By optimizing the process, loops and iterations ensure that fewer lines of code achieve more, focusing on core logic and efficiency.